Arthra

 

 

Dr.A.K.Venkatachalam,

 

Consultant orthopaedic surgeon

 

www.hipsurgery.in

 

Hip arthritis in India affects childish and middle aged persons unlike the west where Primary hip osteoarthritis pre dominantly affects the elderly. Surgery in this group of relatively younger patients requires newer techniques and implants. This condition will shed light on the disease and the current modalities of treatment available.

Types of Hip arthritis

 

Hip arthritis is classified as Primary and secondary Osteoarthritis.

 

Primary osteoarthritis is age related wear and tear arthritis. It is rare in India.

 

Secondary osteoarthritis occurs at a younger age and is more common. Rheumatoid arthritis, avascular necrosis, traumatic arthritis and other connective tissue disorders like SLE, Psoriasis etc. all lead to secondary osteoarthritis.

Rheumatoid arthritis is an auto immune disorder, affects all joints particularly the tiny joints but also does not spare the hip and knees.

 

Avascular necrosis is a condition that reduces the blood supply to the end of the bone. It affects patients with excess alcohol intake, consuming steroids, connective tissue disorders like SLE. Systemic lupus erythematosus (SLE) is a connective tissue disorder affecting primarily childish women A photo sensitive rash on the cheeks, renal involvement and arthritis are some notable facial appearance. Avascular necrosis affects a proportion of the patients with SLE.

 

Gaucherâ??s disease is a genetic storage disorder.

 

Post traumatic arthritis occurs with a severe injury to the hip. Breaks of the ball (top of the femur) or socket (acetabulum) can lead to arthritis with inadequate treatment.

Hip arthritis is very disabling as it is a tiny ball and socket joint unlike the Knee joint which is a large one. In well ahead disease a total hip substitution was recommended by Orthopaedic surgeons until recently. Advances in orthopaedic surgery now cater to the point requirements of these younger patients.

Surgical solutions

 

These are the mainstay of treatment as conservative measures fail to relieve pain. Total Hip substitution (THR) is a time tested surgical procedure and has a success rate of 93 % survivorship at 10 years.

 

The hip joint may need to be replaced with an reproduction joint when it is irreversibly smashed and cannot be salvaged by alternate surgery. The patient complains of pain and restriction of movement. The pain may often be referred to the knee or felt in the knee and no hip symptoms. Irregularly the pain may be felt more in the buttock area rather than in front of the groin.

Who needs a hip substitution?

 

In India, many childish patients with ankylosing spondylitis, avascular necrosis, post septic arthritis, post injury suffer from hip arthritis and are advised a hip substitution for disabling pain. Thus many hip substitution operations are performed in younger patients. The surgery should cater to the enhanced demands on an reproduction joint by younger and more active patients. Naturally an surgical procedure designed for Western elderly patients is not apposite for younger patients.

What is a total hip substitution?

Fig1. Shows the differences between a normal THR on the left and a Proxima hip on the right

In this surgical procedure the ball shaped upper end of the thigh bone (femur) and the socket (acetabulum) are replaced. The ball is replaced with a long metal stem that is fixed into the upper end if the thigh bone. Its upper spherical end articulates with a cup shaped polyethylene socket that is cemented into the pelvis.

 

Conventional hip replacements sacrifice a fantastic deal of normal bone as the head, neck, and upper part of the thigh bone is removed for implantation of the prosthesis. Moreover wear debris from the poly-etheylene liner lead to osteolysis and bone loss. When this initially hip is to be changed or revised with its duration more bone loss occurs. Conventional hips have a tiny ball to reduce friction and wear, but the ill effect of this is an increased risk of dislocation. An average dislocation rate of 3- 4 % has been reported. These implants do not last very longer than 20 years and revision rates of 50% at 20 years have been reported. Survival rates are less satisfactory for the relatively younger active patients. Thus a total hip substitution is not an ideal implant for younger patients less than fifty years ancient who need a new hip.

 

Problems with conventional total hip substitution:

 

Unwarranted bone sacrifice and loss
Increased risk of dislocation
Patients cannot squat or sit thwart legged on the floor with out the risk of dislocation.
Range of movement is less
Patients cannot involve in sports
Poor survival in childish and active patients they require earlier revision.
Revision surgery is hard
The hip feels less like a normal hip
The cup wears with time and plastic from it harms bone
Change in length of the leg with surgery leading to leg length discrepancy.

Why remove normal bone when only the surface of the ball is terrible?

 

This is the judgment behind hip resurfacings. This bone preserving hip resurfacing involves replacing only the diseased bony surfaces of the head of femur and acetabulum. This involves sculpting the head of the femur and covering it with a metal cap and fixing an uncemented socket into the acetabulum to receive the head.

Hip Resurfacing- A bone preserving hip substitution!

 

Preservation of bone and less stress shielding makes it simple to revise this hip if needed. The large head size provides a very stable joint and recreates the sensation of a normal hip joint. Patients have gone back to playing Judo and Squash with this surgical procedure. Advances metallurgy makes the metal on metal articulation likely to survive longer in the childish and active patient. With less metal inside the bone and less invasion of the medullary cavity of the femur, the risk of infection is cut-rate. Rehabilitation is quicker and better.

 

Advantages of hip resurfacing:

 

Allows the patient to squat and sit thwart legged on the floor securely
Allows a normal range of movement
Sacrifices only the surface diseased bone and preserves normal bone
Imparts a more normal sensation
The joint is likely to last longer even in younger and active patients.
Earlier and quicker rehabilitation
Less risk of dislocation
Simpler to revise if needed.
No leg length discrepancy

Proxima hip substitution â?? A perfect bone preserving hip substitution?

 

This is the latest addition to the armamentarium of the hip surgeon in India. It is a bone preserving hip substitution.

 

In this surgical procedure, the entire diseased head of the femur is removed. The lining of the hip socket is resurfaced with a metal cup. A tiny uncemented hip with a fleeting stem called the Proxima hip is impacted into the upper end of the femur or thigh bone.

The size of the implant matches the untreated one and hence the risk of dislocation is nearly eliminated. It is recommended when the bony destruction is well ahead and hence unsuitable for resurfacing and a total hip substitution would be overkill. The advantages of the Proxima are

 

suited for minimally invasive surgery
No thigh pain
Metal on metal â?? confers longevity
Conformity to normal size eliminates risk of dislocation
Ability to right biomechanical abnormalities makes this superior to resurfacing.
Imparts a more normal sensation
Allows a normal range of movement and normal activities